noun which may take the genitive case particle 'no', noun
Describes a diagonal direction or position, often used with に to mean 'diagonally' or 'at an angle'. Common in everyday spatial descriptions.
See also: 斜交 (しゃこう)
はすかいに座っている人と目が合った。
I made eye contact with the person sitting diagonally across from me.
その店は交差点のはすかいにある。
The shop is diagonally across the intersection.
斜め is the most common word for 'diagonal' or 'slanting' and can be used broadly. はすかい is more specific to a diagonal line or position, often implying a corner-to-corner relationship.
The origin is uncertain. It may be related to 斜 (はす, 'diagonal') and 交い (かい, 'crossing'), but the exact derivation is unclear.